@JosephWright I just failed with my first use of xparse. Could you have a look on this command please: `\documentclass{article}
\usepackage{siunitx}
\usepackage{xparse}
\ExplSyntaxOn
\makeatletter
\NewDocumentCommand\angRange{o o m m}{
\leavevmode
\group_begin:
\IfNoValueTF {#1}
{ \@@_list_units:nnn {#3} {#4} { parse-numbers=false } }
{
\keys_set:nn { siunitx } {#1}
\@@_list_units:nnn {\ang[parse-numbers=true,#2]{#3}} {\ang[parse-numbers=true,#2]{#4}} {parse-numbers=false, #1}
}
\group_end:
}
\makeatother